Maayke Hunfeld

36 Chapter 2 review shows us that the described neuromonitoring methods must be interpreted with extreme caution in the context of the patient’s clinical neurological status. Even for EEG, with the majority of studies in this review, patients with ‘poor’ patterns may have a ‘good’ outcome’ and vice versa. It must be emphasized that the value of predicting ‘short-term’ outcome is itself dubious since the long-term trajectory of outcome after CA is not well studied and subject to a complex interaction of socioeconomic factors and value judgements about meaningful quality of life. Also the data on MRI, SEP and biomarkers is sparse and almost uninterpretable. Furthermore, the current available data, which is mostly retrospective and heterogeneous, has small to moderate sample sizes (median pediatric sample size post-CA n=35, IQR 28-64) using often crude outcome measures. Therefore, no evidence-based statement can be given on which neuromonitoring method should be implemented. However this does not reduce the potential of current neuromonitoring modalities and we discuss their promise below. The current studies provide insight into the challenges in performing outcome studies after pediatric CA. First, the pediatric population is a developing group. The different ages (ranging from 1 mo to 17 yr) hamper meaningful outcome comparison. Children of varying age have age-specific (cerebral) physiology and are in different developmental stages. In children (especially preschool) with brain damage, growing into deficit can occur later in life. Second, many additional investigations (e.g. EEG, MRI) in multiple studies were only done when clinically indicated and clinicians were unblinded to the results. This can lead to selection bias and self-fulfilling prophecies in relation to patient outcome (e.g. decision-making regarding withdrawal of life- sustaining therapies). Third, the majority of neuromonitoring studies included both OHCA and OHCA with different etiologies, resulting in heterogeneous patient groups. Finally, in the majority of studies, outcome was measured using gross outcome scales (e.g. PCPC, GOS). But how to define outcome? Can we express this using only a crude functional measure such as a PCPC score and how does this reflect the health-related quality of life? Furthermore, could the meaning of quality of life vary among health care professionals, parents and patients due to differences in cultural aspects, beliefs and socio-economic factors? In this review, we could only identify one study that investigated quality of life (38). The same applies to neuropsychological assessment and social participation which also contribute to overall outcome. Equally important is the follow-up interval. In most studies, follow-up was short term (i.e. evaluation at hospital or PICU discharge). We must emphasize that long-term follow-up (in adolescents at least 1 yr after the event and in pre-school children at least 5 to 10 yr) is extremely important as outcome often changes within the first years after CA (38) and patients may grow into deficit as they become older and are increasingly expected to participate in society.